inveniogc: clean more temporary files
inveniogc: clean more temporary files

* Removes temporary file preview icons websubmit_icon_creator_*
* Removes temporary file stamps websubmit_file_stamper_*
* Removes temporary WebJournal XML update files webjournal_publish_*
* Removes temporary CKEditor file attachments in CFG_PREFIX/var/tmp/attachfile/

inveniosoftware/invenio-accounts,inspirehep/invenio-accounts,inspirehep/invenio-accounts,inveniosoftware/invenio-accounts,tiborsimko/invenio-accounts,inveniosoftware/invenio-accounts,tiborsimko/invenio-accounts,inspirehep/invenio-accounts,tiborsimko/invenio-accounts